%序列的乘积
function[y,n]=seqmult(x1,n1,x2,n2)
    n=min(min(n1),min(n2)):max(max(n1),max(n2));
    y1=zeros(1,length(n));y2=y1;
    y1(find((n>=min(n1))&(n<=max(n1))==1))=x1;
    y2(find((n>=min(n2))&(n<=max(n2))==1))=x2;
    y=y1.*y2;
end